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<h1 class="title">calculator.js 示例文件</h1>
<span class="subtitle">demos/calqlatr/content/calculator.js</span>
<!-- $$$demos/calqlatr/content/calculator.js-description -->
<div class="descr"> <a name="details"></a>
<pre class="js">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2017 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
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  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  var <span class="name">curVal</span> = <span class="number">0</span>
  var <span class="name">memory</span> = <span class="number">0</span>
  var <span class="name">lastOp</span> = <span class="string">&quot;&quot;</span>
  var <span class="name">previousOperator</span> = <span class="string">&quot;&quot;</span>
  var <span class="name">digits</span> = <span class="string">&quot;&quot;</span>

  <span class="keyword">function</span> <span class="name">disabled</span>(<span class="name">op</span>) {
      <span class="keyword">if</span> (<span class="name">digits</span> <span class="operator">==</span> <span class="string">&quot;&quot;</span> <span class="operator">&amp;&amp;</span> !((<span class="name">op</span> <span class="operator">&gt;=</span> <span class="string">&quot;0&quot;</span> <span class="operator">&amp;&amp;</span> <span class="name">op</span> <span class="operator">&lt;=</span> <span class="string">&quot;9&quot;</span>) <span class="operator">||</span> <span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;.&quot;</span>))
          <span class="keyword">return</span> <span class="number">true</span>
      <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">'='</span> <span class="operator">&amp;&amp;</span> <span class="name">previousOperator</span>.<span class="name">length</span> <span class="operator">!=</span> <span class="number">1</span>)
          <span class="keyword">return</span> <span class="number">true</span>
      <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;.&quot;</span> <span class="operator">&amp;&amp;</span> <span class="name">digits</span>.<span class="name">toString</span>().<span class="name">search</span>(/\./) <span class="operator">!=</span> -<span class="number">1</span>) {
          <span class="keyword">return</span> <span class="number">true</span>
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;√&quot;</span> <span class="operator">&amp;&amp;</span>  <span class="name">digits</span>.<span class="name">toString</span>().<span class="name">search</span>(/-/) <span class="operator">!=</span> -<span class="number">1</span>) {
          <span class="keyword">return</span> <span class="number">true</span>
      } <span class="keyword">else</span> {
          <span class="keyword">return</span> <span class="number">false</span>
      }
  }

  <span class="keyword">function</span> <span class="name">digitPressed</span>(<span class="name">op</span>)
  {
      <span class="keyword">if</span> (<span class="name">disabled</span>(<span class="name">op</span>))
          <span class="keyword">return</span>
      <span class="keyword">if</span> (<span class="name">digits</span>.<span class="name">toString</span>().<span class="name">length</span> <span class="operator">&gt;=</span> <span class="name">display</span>.<span class="name">maxDigits</span>)
          <span class="keyword">return</span>
      <span class="keyword">if</span> (<span class="name">lastOp</span>.<span class="name">toString</span>().<span class="name">length</span> <span class="operator">==</span> <span class="number">1</span> <span class="operator">&amp;&amp;</span> ((<span class="name">lastOp</span> <span class="operator">&gt;=</span> <span class="string">&quot;0&quot;</span> <span class="operator">&amp;&amp;</span> <span class="name">lastOp</span> <span class="operator">&lt;=</span> <span class="string">&quot;9&quot;</span>) <span class="operator">||</span> <span class="name">lastOp</span> <span class="operator">==</span> <span class="string">&quot;.&quot;</span>) ) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">digits</span> <span class="operator">+</span> <span class="name">op</span>.<span class="name">toString</span>()
          <span class="name">display</span>.<span class="name">appendDigit</span>(<span class="name">op</span>.<span class="name">toString</span>())
      } <span class="keyword">else</span> {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">op</span>
          <span class="name">display</span>.<span class="name">appendDigit</span>(<span class="name">op</span>.<span class="name">toString</span>())
      }
      <span class="name">lastOp</span> <span class="operator">=</span> <span class="name">op</span>
  }

  <span class="keyword">function</span> <span class="name">operatorPressed</span>(<span class="name">op</span>)
  {
      <span class="keyword">if</span> (<span class="name">disabled</span>(<span class="name">op</span>))
          <span class="keyword">return</span>
      <span class="name">lastOp</span> <span class="operator">=</span> <span class="name">op</span>

      <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;±&quot;</span>) {
              <span class="name">digits</span> <span class="operator">=</span> <span class="name">Number</span>(<span class="name">digits</span>.<span class="name">valueOf</span>() <span class="operator">*</span> -<span class="number">1</span>)
              <span class="name">display</span>.<span class="name">setDigit</span>(<span class="name">display</span>.<span class="name">displayNumber</span>(<span class="name">digits</span>))
              <span class="keyword">return</span>
          }

      <span class="keyword">if</span> (<span class="name">previousOperator</span> <span class="operator">==</span> <span class="string">&quot;+&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">Number</span>(<span class="name">digits</span>.<span class="name">valueOf</span>()) <span class="operator">+</span> <span class="name">Number</span>(<span class="name">curVal</span>.<span class="name">valueOf</span>())
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">previousOperator</span> <span class="operator">==</span> <span class="string">&quot;−&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">Number</span>(<span class="name">curVal</span>.<span class="name">valueOf</span>()) <span class="operator">-</span> <span class="name">Number</span>(<span class="name">digits</span>.<span class="name">valueOf</span>())
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">previousOperator</span> <span class="operator">==</span> <span class="string">&quot;×&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">Number</span>(<span class="name">curVal</span>) <span class="operator">*</span> <span class="name">Number</span>(<span class="name">digits</span>.<span class="name">valueOf</span>())
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">previousOperator</span> <span class="operator">==</span> <span class="string">&quot;÷&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">Number</span>(<span class="name">curVal</span>) <span class="operator">/</span> <span class="name">Number</span>(<span class="name">digits</span>.<span class="name">valueOf</span>())
      }

      <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;+&quot;</span> <span class="operator">||</span> <span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;−&quot;</span> <span class="operator">||</span> <span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;×&quot;</span> <span class="operator">||</span> <span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;÷&quot;</span>) {
          <span class="name">previousOperator</span> <span class="operator">=</span> <span class="name">op</span>
          <span class="name">curVal</span> <span class="operator">=</span> <span class="name">digits</span>.<span class="name">valueOf</span>()
          <span class="name">digits</span> <span class="operator">=</span> <span class="string">&quot;&quot;</span>
          <span class="name">display</span>.<span class="name">displayOperator</span>(<span class="name">previousOperator</span>)
          <span class="keyword">return</span>
      }

      <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;=&quot;</span>) {
          <span class="name">display</span>.<span class="name">newLine</span>(<span class="string">&quot;=&quot;</span>, <span class="name">digits</span>.<span class="name">valueOf</span>())
      }

      <span class="name">curVal</span> <span class="operator">=</span> <span class="number">0</span>
      <span class="name">previousOperator</span> <span class="operator">=</span> <span class="string">&quot;&quot;</span>

      <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;1/x&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> (<span class="number">1</span> <span class="operator">/</span> <span class="name">digits</span>.<span class="name">valueOf</span>()).<span class="name">toString</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;x^2&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> (<span class="name">digits</span>.<span class="name">valueOf</span>() <span class="operator">*</span> <span class="name">digits</span>.<span class="name">valueOf</span>()).<span class="name">toString</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;Abs&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> (<span class="name">Math</span>.<span class="name">abs</span>(<span class="name">digits</span>.<span class="name">valueOf</span>())).<span class="name">toString</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;Int&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> (<span class="name">Math</span>.<span class="name">floor</span>(<span class="name">digits</span>.<span class="name">valueOf</span>())).<span class="name">toString</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;√&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">Number</span>(<span class="name">Math</span>.<span class="name">sqrt</span>(<span class="name">digits</span>.<span class="name">valueOf</span>()))
          <span class="name">display</span>.<span class="name">newLine</span>(<span class="string">&quot;√&quot;</span>, <span class="name">digits</span>.<span class="name">valueOf</span>())
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;mc&quot;</span>) {
          <span class="name">memory</span> <span class="operator">=</span> <span class="number">0</span>;
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;m+&quot;</span>) {
          <span class="name">memory</span> <span class="operator">+=</span> <span class="name">digits</span>.<span class="name">valueOf</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;mr&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">memory</span>.<span class="name">toString</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;m-&quot;</span>) {
          <span class="name">memory</span> <span class="operator">=</span> <span class="name">digits</span>.<span class="name">valueOf</span>()
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;backspace&quot;</span>) {
          <span class="name">digits</span> <span class="operator">=</span> <span class="name">digits</span>.<span class="name">toString</span>().<span class="name">slice</span>(<span class="number">0</span>, -<span class="number">1</span>)
          <span class="name">display</span>.<span class="name">clear</span>()
          <span class="name">display</span>.<span class="name">appendDigit</span>(<span class="name">digits</span>)
      } <span class="keyword">else</span> <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;Off&quot;</span>) {
          <span class="name">Qt</span>.<span class="name">quit</span>();
      }

      <span class="comment">// Reset the state on 'C' operator or after</span>
      <span class="comment">// an error occurred</span>
      <span class="keyword">if</span> (<span class="name">op</span> <span class="operator">==</span> <span class="string">&quot;C&quot;</span> <span class="operator">||</span> <span class="name">display</span>.<span class="name">isError</span>) {
          <span class="name">display</span>.<span class="name">clear</span>()
          <span class="name">curVal</span> <span class="operator">=</span> <span class="number">0</span>
          <span class="name">memory</span> <span class="operator">=</span> <span class="number">0</span>
          <span class="name">lastOp</span> <span class="operator">=</span> <span class="string">&quot;&quot;</span>
          <span class="name">digits</span> <span class="operator">=</span> <span class="string">&quot;&quot;</span>
      }
  }

</pre>
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<!-- @@@demos/calqlatr/content/calculator.js -->
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